S. B. Moore

A Comparison of Plasmapheresis Versus High-Dose IVIG Desensitization in Renal Allograft Recipients with High Levels of Donor Specific Alloantibody

Several protocols allow for the successful transplantation of sensitized renal allograft recipients, yet no one best method has emerged. The aim of the current study was to compare the efficacy of high‐dose IVIG with two different plasmapheresis (PP)‐based regimens in kidney transplant recipients with high levels of donor specific alloantibody (DSA) defined as a positive T‐cell cytotoxicity crossmatch. With the primary goal of achieving a negative crossmatch, we employed three protocols sequentially between April 2000 and May 2005: (i) PP, low‐dose IVIG, anti‐CD20 antibody (n = 32); (ii) high‐dose IVIG (n = 13); and (iii) PP, low‐dose IVIG, anti‐CD20 antibody and pre‐transplant Thymoglobulin combined with post‐transplant DSA monitoring (n = 16). IVIG decreased DSA activity in all treated patient, yet only 38% (5/13) achieved a negative crossmatch. In contrast, a negative crossmatch was achieved in 84% in PP group and 88% in the PP/monitoring group (p < 0.01 vs. IVIG). Even with a negative crossmatch, the rejection rates were 80% (IVIG), 37% (PP) and 29% (PP/monitoring), respectively, (p < 0.05 IVIG vs. PP). We conclude that multiple PP treatments leads to more reproducible desensitization and lower humoral rejection rates than a single high‐dose of IVIG, but that no regimen was completely effective in preventing humoral rejection.

Transplant Glomerulopathy: Subclinical Incidence and Association with Alloantibody

Transplant glomerulopathy (TG) usually has been described as part of a constellation of late chronic histologic abnormalities associated with proteinuria and declining function. The current study used both protocol and clinically‐indicated biopsies to investigate clinical and subclinical TG, their prognosis and possible association with alloantibody. We retrospectively studied 582 renal transplants with a negative pre‐transplant T‐cell complement dependent cytotoxicity crossmatch. TG was diagnosed in 55 patients, 27 (49%) based on protocol biopsy in well‐functioning grafts. The cumulative incidence of TG increased over time to 20% at 5 years. The prognosis of subclinical TG was equally as poor as TG diagnosed with graft dysfunction, with progressive worsening of histopathologic changes and function. Although TG was associated with both acute and chronic histologic abnormalities, 14.5% of TG biopsies showed no interstitial fibrosis or tubular atrophy, while 58% (7/12) of biopsies with severe TG showed only minimal abnormalities. TG was associated with acute rejection, pretransplant hepatitis C antibody positivity and anti‐HLA antibodies (especially anti‐Class II), with the risk increasing if the antibodies were donor specific. We suggest that subclinical TG is an under‐recognized cause of antibody‐mediated, chronic renal allograft injury which may be mechanistically distinct from other causes of nephropathy.

Histologic findings one year after positive crossmatch or ABO blood group incompatible living donor kidney transplantation.

Recent protocols have allowed successful positive crossmatch (+XM) and ABO incompatible (ABOI) kidney transplantation, although their long‐term outcome is not clear. To begin to assess this issue we compared protocol biopsies performed 12 months posttransplant in 37 +XM, 24 ABOI and 198 conventional allografts. Although the majority in all three groups had only minimal histologic changes, transplant glomerulopathy (TG) was significantly increased in +XM (22% vs. 13% ABOI vs. 8% conventional, p = 0.015), and correlated with prior humoral rejection (HR) by multivariate analysis (odds ratio 17.5, p ≤ 0.0001). Patients with a prior history of HR also had a significant increase in interstitial fibrosis (No HR 54% vs. HR 86%, p = 0.045). In the absence of HR no difference in histologic changes was seen between groups, although all three groups had a demonstrable mild increase in interstitial fibrosis from biopsies performed at the time of transplant. Thus, although HR is associated with an increase in TG, in its absence allograft histology is similar in +XM, ABOI and conventional allografts 1 year posttransplant.

The dose of infused lymphocytes in the autograft directly correlates with clinical outcome after autologous peripheral blood hematopoietic stem cell transplantation in multiple myeloma

Absolute lymphocyte count at day 15 (ALC-15) after autologous peripheral blood hematopoietic stem cell transplantation (APHSCT) is an independent prognostic factor for survival in multiple myeloma (MM); however, factors affecting ALC-15 in MM remain unknown. We hypothesized that the dose of infused peripheral blood autograft lymphocytes (autograft absolute lymphocyte count: A-ALC) impacts ALC-15 recovery. Between 1989 and 2001, 267 consecutive MM patients underwent APHSCT. We set out to determine the correlation between A-ALC and ALC-15 and the utility of A-ALC as a marker for ALC-15 recovery. A-ALC was found to be both a strong predictor for area under curve (AUC=0.93; P=0.0001) and strongly correlated with (rs=0.83; P=0.0001) ALC-15 recovery. Higher infused A-ALC was significantly correlated with an ALC-15⩾500/μl. In addition, median post-transplant overall survival (OS) and time to progression (TTP) were longer in patients who received an A-ALC⩾0.5 × 109 lymphocytes/kg versus A-ALC <0.5 × 109 lymphocytes/kg (58 vs 30 months, P=0.00022; 22 vs 15 months, P<0.00012, respectively). Multivariate analysis demonstrated A-ALC as an independent prognostic indicator for OS and TTP. These results indicate that an infused dose of autograft lymphocytes significantly impacts clinical outcome post-APHSCT in MM.

Trends in the incidence of delayed hemolytic and delayed serologic transfusion reactions

BACKGROUND: An increasing incidence of delayed hemolytic and delayed serologic transfusion reactions (DHTRs/DSTRs) has been seen at the Mayo Clinic since 1978. Recently, the average length of stay (LOS) for inpatients and the average number of red cell transfusions per inpatient (TPI) decreased, and the albumin and papain technique for RBC antibody detection was replaced by a polyethylene glycol technique. These changes may have affected the incidence of DHTRs/DSTRs.

Kidney Transplantation in Patients with Antibodies against Donor HLA Class II

The immunologic risk associated with donor‐specific antibodies (DSA) against Class II human leukocyte antigens (HLA) in kidney transplant (KTx) recipients is unclear. The aim of this study was to determine the outcome of KTx when DSA was detected only against HLA Class II. To isolate the impact of anti‐Class II DSA, we retrospectively analyzed 12 KTx recipients who at baseline had a positive B‐cell flow cytometric crossmatch (FXM) and a negative T‐cell FXM. Using alloantibody specification analysis, 58.3% (7/12) had DSA against donor Class II and 41.7% had no demonstrable DSA. Biopsy‐proven AMR occurred in 57% (4/7) in the Class II+ group and 0% in the Class II− group (p > 0.05). Peritubular capillaries stained positive for C4d in 86% (6/7) of the Class II+ patients and in 40% (2/5) of the Class II− patients (p > 0.05). One patient in the Class II+ group lost their graft at 3 months to accelerated transplant glomerulopathy, while all other grafts were functioning 3–37 months posttransplant despite the persistence of anti‐Class II DSA. We conclude that KTx recipients with clearly defined anti‐Class II DSA are at risk for humoral rejection suggesting that desensitization and/or close posttransplant monitoring may be needed to prevent AMR.

The differentiation of delayed hemolytic and delayed serologic transfusion reactions: incidence and predictors of hemolysis

BACKGROUND: After differentiation of the entities of clinically detectable delayed hemolytic (DHTR) and delayed serologic transfusion reactions (DSTR), previous investigators calculated a DHTR:DSTR incidence ratio of 18:72 from a retrospective review of patients with serologic evidence of DHTR or DSTR. There are no published data on factors that may influence the occurrence of DHTR versus DSTR in a given patient. STUDY DESIGN AND METHODS: Retrospective review was conducted of 292 patients at the Mayo Clinic who, between 1980 and 1992, received a clinical diagnosis of DHTR or DSTR concurrently with a serologic diagnosis. Red cell alloantibody specificity, the activity of the patients reticuloendothelial system, and concurrent immunosuppression were evaluated as potential predictors of the occurrence of DHTR versus DSTR in different patients. RESULTS: The incidence of DHTR or DSTR was 1 in 1899 allogeneic red cell units transfused, with a DHTR:DSTR ratio of 36:64. Alloantibody specificity was the only variable that affected the occurrence of DHTR versus DSTR at the clinical level, with the anti‐Jka and anti‐Fya specificities, as well as multiple coexisting specificities, significantly associated with detectable hemolysis (p < 0.05). CONCLUSION: Clinically detectable DHTRs are found to occur more commonly than previously believed when the clinical and serologic diagnoses are made concurrently and appropriate work‐ups for hemolysis are ordered. The association of certain alloantibody specificities with detectable DHTRs may have implications for clinical transfusion practice.

Comparison of the polyethylene glycol antiglobulin test and the use of enzymes in antibody detection and identification

BACKGROUND: The polyethylene glycol indirect antiglobulin test for detection of red cell antibodies was compared with a proven, highly sensitive test system using papain. STUDY DESIGN AND METHODS: Parallel, prospective testing of 1508 samples with polyethylene glycol and with albumin and papain evaluated the sensitivity and specificity of polyethylene glycol. Retrospective analysis of antibody specificities was performed for the 2 years before and the 2 years after the institution of polyethylene glycol testing. RESULTS: Of 1508 prospective screens, 53 (3.5%) had discordant results: 5 were positive only in polyethylene glycol and 48 were positive only in albumin and papain. Upon antibody identification, the 5 samples that were positive only in polyethylene glycol showed 1 anti‐D, 2 warm autoantibodies, and 2 false‐positive results. The 48 samples that were positive only in albumin and papain showed 1 each of the following: anti‐Le(b); anti‐P1; anti‐S; high‐titer, low‐avidity antibody; and cold autoantibody; there were 43 false‐positive results. False‐positive results totaled 12 (0.8%) with polyethylene glycol and 53 (3.5%) with albumin and papain. The retrospective analysis of antibody specificity with polyethylene glycol showed a significant increase in the detection of Fy(a) and/or Fy(b) (p < 0.0002) and Jk(b) (p < 0.0002) antibodies and a decrease in the detection of Le(a) and/or Le(b) antibodies (p < 0.0002). CONCLUSION: Polyethylene glycol retained the high sensitivity of the albumin and papain, while significantly lowering the number of false‐ positive results and decreasing the detection of antibodies of doubtful clinical significance.

Apheresis instrument settings influence infused absolute lymphocyte count affecting survival following autologous peripheral hematopoietic stem cell transplantation in non-Hodgkin's lymphoma: the need to optimize instrument setting and define a lymphocyte collection target

Autograft absolute lymphocyte count (A-ALC) is an independent prognostic factor for survival after autologous peripheral blood hematopoietic stem cell transplantation (APHSCT) for non-Hodgkins lymphoma (NHL). Factors enhancing A-ALC collections are unknown. We hypothesize that apheresis instrument settings could affect A-ALC. Data from 127 NHL patients collected from 15 January 1999 to 30 July 2004 using a single apheresis instrument (COBE Spectra (SP), Baxter Amicus (AM), and CS3000 Plus (CS)) were analyzed. The primary end point of the study was to assess the correlation between apheresis instrument settings and A-ALC. The secondary end point was to determine the effect of apheresis instrument on survival post-APHSCT. Patients collected using SP achieved higher A-ALC compared to AM (with modified settings) or CS (P<0.05) and demonstrated superior overall (OS) and progression-free survival (PFS) (P<0.03). Multivariate analysis demonstrated A-ALC and not the apheresis instrument as an independent prognostic factor for OS and PFS, cancelling the prognostic effect of the apheresis instruments observed in the univariate analysis. The survival advantage observed by SP was from the higher A-ALC collected compared to AM and CS. These data suggest that apheresis instrument settings should be optimized to collect CD34+ cells as well as an A-ALC target, with direct impact on survival post-APHSCT.